Руководство По Устранению Ошибки для Cisco Cisco Packet Data Gateway (PDG)
Cisco ASR 5000 Series Enhanced Feature Configuration Guide ▄
OL-22982-01
Chapter 37
Session Recovery
In the telecommunications industry, over 90 percent of all equipment failures are software-related. With robust
hardware failover and redundancy protection, any card-level hardware failures on the system can quickly be corrected.
However, software failures can occur for numerous reasons, many times without prior indication. For this reason, we
have introduced a new solution to recover subscriber sessions in the event of failure.
hardware failover and redundancy protection, any card-level hardware failures on the system can quickly be corrected.
However, software failures can occur for numerous reasons, many times without prior indication. For this reason, we
have introduced a new solution to recover subscriber sessions in the event of failure.
The Session Recovery feature provides seamless failover and reconstruction of subscriber session information in the
event of a hardware or software fault within the system preventing a fully connected user session from being
disconnected.
event of a hardware or software fault within the system preventing a fully connected user session from being
disconnected.
This feature is available for the following functions:
PDSN services supporting simple IP, Mobile IP, and Proxy Mobile IP
GGSN services for IPv4 and PPP PDP contexts
SGSN services (3G and 2.5G services) for IPv4 and PPP PDP contexts
HA services supporting Mobile IP and/or Proxy Mobile IP session types with or without per-user Layer 3 tunnels
LNS session types
IPSG-only systems
Any session needing L2TP LAC support (excluding regenerated PPP on top of an HA/GGSN session)
Session recovery is not supported for the following functions:
Mobile IP sessions with L2TP
Multiple MIP sessions
Destination-based accounting recovery
Any session using IPv6 (PDSN/GGSN/SGSN/LNS)
Any session needing L2TP LAC support (including regenerated PPP on top of an HA/GGSN session)
GGSN network initiated connections
MIP session with multiple concurrent bindings
MIP/L2TP with IPSEC integration
GGSN session using more than 1 service instance
Important:
Session Recovery can only be enabled through a feature use license key. If you have not previously
purchased this enhanced feature, contact your sales representative for more information.
When session recovery occurs, the system reconstructs the following subscriber information:
Data and control state information required to maintain correct call behavior.
A minimal set of subscriber data statistics; required to ensure that accounting information is maintained.
A best-effort attempt to recover various timer values such as call duration, absolute time, and others.